Ridges of paint along masks

De-masking while the paint is still relatively wet DOES work! It's how I was taught to paint real aircraft 26 years ago. The demarcation line lays down with no ridge.

I would suggest if you don't already have one, invest in a good airbrush.  My first AB was a Badger 200 which I still have and is my go-to brush for a lot of my painting jobs.  Airbrushes have way more control than the rattle-cans.

If the finish will be matt, one can sand those ridges with very fine paper- 1500 or finer, and the paint will not show the sanding.

I've found that using an air brush rather than spray cans helps the problem because the cans blast far too much paint.

I read in FSM a general tip that to avoid ridges, remove the masking ASAP after spraying; don't give the paint time to set and build a ridge. "Shrug". Not sure if it works or not.

Yeah the red is gloss. I'll try with painting with a flat at a 90 and slowly build up the paint. Thanks guys.

Spraying towards the masking will cause a build up of paint - spraying at 90° or more to the masking edge will prevent paint accumulating against the edge.

Was the red gloss?  You can use flat red and then spray a gloss coat over that.  Gloss paints have to be sprayed on a bit thicker which contributes to the ridges.  But with rattle cans it may be hard to eliminate the ridges no matter what.